title: Radial partition fluorescent immunoassay of thyrotropin. Analytic evaluation and clinical correlation.
abstract: The authors evaluated the analytic and clinical performance of a sensitive radial partition fluorescent enzyme immunoassay for thyrotropin (TSH) performed on Stratus and compared it with a nonsensitive radioimmunoassay (RIA) method. Sensitivity of 0.15 mIU/L was obtained, and precision, specificity, and linearity were acceptable. A good correlation was observed between the two assays in samples from 311 hospitalized patients (r = 0.976). Stratus TSH results were outside the reference range for 20% of clinically euthyroid patients (n = 126), and 2.4% had undetectable levels. The clinically hyperthyroid group (n = 11) with the exception of one patient had TSH values below 0.2 mIU/L. Only 39% of hypothyroid patients on thyroid hormone replacement (n = 74) had TSH values in the reference range, with 38% and 23% exhibiting low and high values, respectively. All untreated primary hypothyroid patients (n = 8) had elevated TSH concentrations. The authors conclude that this sensitive TSH assay is useful for diagnosing hyperthyroidism when there is a clinical suspicion but cannot be recommended for thyroid screening in hospitalized patients.
authors.affiliation: Department of Pathology, Washington University Medical Center, St. Louis, MO 63110.
authors.forename: D B
authors.initials: DB
authors.lastname: Sacks
authors.forename: M M
authors.initials: MM
authors.lastname: Lim
authors.forename: R
authors.initials: R
authors.lastname: Valdes
authors.forename: G
authors.initials: G
authors.lastname: Kessler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001322:Autoanalysis; D001663:Bilirubin / Q000097:blood; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D007037:Hypothyroidism / Q000097:blood; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D011863:Radioimmunoassay; D012016:Reference Values; D013972:Thyrotropin / Q000097:blood*
chemical_list: D005456:Fluorescent Dyes; D013972:Thyrotropin; D001663:Bilirubin